Mannich bases containing tertiary amines and fuel compositions containing said mannich bases

ABSTRACT

Mannich condensation products useful in gasoline as carburetor detergents; the condensation compositions having the formula &lt;IMAGE&gt;   wherein Z is an alkyl - and hydroxy - substituted benzyl group wherein the alkyl has 20 to 1000 carbon atoms, n is 2 or 3; R is an alkyl of 1 to 20 carbon atoms; a, x and c are each 0 or 1; and b is 0 to 5; with the provisos that when a = 0, then b is at least 1 and c = 1; when a = 1 and x = 0, then b and c = 0; and when a = 1 and x = 1, then c = 1.

BACKGROUND OF THE INVENTION

This invention concerns Mannich condensation products useful asadditives in gasoline and lubricating oils.

The accumulation of deposits in certain critical area of the fuel intakesystem in an internal combustion engine frequently causes difficulties.Thus, deposit accumulation on the carburetor throttle plate and in thearea surrounding the throttle plate can cause rough idling, enginestalling and the loss of fuel economy. A very high accumulation ofdeposits on intake valves can lead to improper valve closing, sluggishvalve action, loss of power and even valve burning. It is known that theuse of a particular gasoline additive to overcome one type of difficultyvery often causes other difficulties. For example, the use of a highlypolar carburetor detergent to control carburetor deposits may give riseto increased intake valve deposits.

Certain condensation products of an alkylphenol, an aldehyde and anamine, commonly known as Mannich Bases, are effective carburetordetergents in gasoline. In common with most other carburetor detergents,however, these Mannich Bases can cause significantly increased intakevalve deposits, particularly when used in low concentrations.

The present invention concerns a novel class of Mannich Bases whichprovide carburetor detergency. In contrast to the Mannich Bases of theart, the present compositions at low concentrations have a minimaleffect upon the intake valve deposit weight increase and at highconcentrations provide control or even reduction of the deposit weights.

SUMMARY OF THE INVENTION

This invention concerns compositions of the formula ##STR2## wherein Zis an alkyl- and hydroxy-substituted benzyl group wherein the alkyl has20 to 1000 carbon atoms; n is 2 or 3; R is an alkyl of 1 to 20 carbonatoms; a, x, and c are each 0 or 1; and b is 0 to 5; with the provisosthat when a =0, then b is at least 1 and c =1; when a = 1 and x = 0,then b and c =0; when a = 1 and x = 1, then c = 1.

Preferred compositions are those wherein the alkyl group in Z has 50 to200 carbon atoms and wherein:

    i. n = 2, a = 1, x = 1, b =0 and c = 1,

    ii. n = 2, a = 1, x = 0, b = 0 and c = 0,

    iii. n = 2, a = 0, b = 1 to 5 and c = 1, and

    iv n = 3, a = 0, b = 1 to 5 and c = 1.

Most preferred are compositions wherein the alkyl group in Z has 50 to75 carbon atoms having the formulas: ##STR3## wherein R is an alkylgroup to of 1 to 4 carbon atoms, preferably one carbon atom.

Also included within the scope of this invention are gasolinecompositions containing from about 0.005 to 0.06 weight percent (12.5 to150 pounds per thousand barrels) of the amine compositions of thisinvention. The amine compositions can also be used in lubricating oilsto provide detergency. Normally, the lubricating oils will contain fromabout 0.5 weight percent to 15 weight percent of the inventioncomposition. The invention also concerns a concentrated solution of theamine compositions in a hydrocarbon solvent boiling in the gasolineboiling range of 32° C to 205° C, said composition being present at from10 to 90 weight percent of the solution.

DETAILS OF THE INVENTION

The amine compositions of this invention can be prepared by knownmethods such as alkylation of a suitable amine with an alkyl- andhydroxy-substituted benzyl halide. They are preferably prepared by theMannich reaction wherein an alkylphenol, a suitable amine andformaldehyde are mixed and heated to a temperature in the range of about80° to 200° C, for a time sufficient for the reaction to occur. Whilenot required, an acidic catalyst such as hydrochloric acid or sulphuricacid can be used. The reaction mixture is kept at the reactiontemperature until sufficient water of condensation has been evolved andremoved.

The reaction can be carried out in the absence of a solvent but it ispreferable to use one, especially one which distills with waterazeotropically. Suitable solvents are hydrocarbons boiling in thegasoline boiling range of about 32° C to 205° C and include amongothers: hexane, cyclohexane, n-octane, isooctane, benzene, toluene,xylene and mixtures thereof. The amount of solvent used is not criticalbut when used it is usually employed in an amount of about 10% to 90% byweight of the total reaction mixture.

The use of a solvent not only facilitates the reaction but some or allof the solvent can be retained with the reaction product to produce theadditive composition as a solution. Such a solution makes handling andincorporation of the composition into gasoline easier. The solution willpreferably contain 40% to 80%, more preferably 50% to 75% by weight ofthe invention composition in a single solvent or a mixture of solventssuch as those listed above.

The alkylphenol useful in the preparation of the invention compositionis preferably a monoalkylphenol where the alkyl group has 20 to 1000carbon atoms. Alkylphenols are well known and any of the several methodsknown in the art, such as the Friedel-Craft alkylation of phenol with anolefin, can be used to their preparation. Where the compositions areintended to provide control of quick-heat intake manifold deposits it ispreferred, although not necessary, that the alkylphenol have an alkylgroup of 50 to 1000 carbon atoms and that at least about 60% of thealkyl group be located para to the phenolic hydroxyl group. Such asalkylphenol can be prepared by the alkylation of phenol with amonoolefin of 50 to 1000 carbon atoms using boron trifluoride catalystand a reaction temperature below about 65° C, preferably in the range40° to 50° C.

The olefin used to alkylate the phenol is a monoolefin of 20 to 1000carbon atoms. Preferred are monoolefins containing from 50 to 100 carbonatoms prepared from polymerization of low molecular weight olefin of 2to 6 carbon atoms either as a homopolymer or as a copolymer. The mostpreferred monoolefins are homopolymers of propylene having 50 to 75carbon atoms.

As mentioned, the alkyl-substituted phenol is preferably amonoalkylphenol but the presence of minor amounts of di- ortri-alkylphenols including those which may be found in the alkylationreactions are not objectionable.

The formaldehyde reactant can be free formaldehyde, an aqueous solutionof formaldehyde or a polymerized form of formaldehyde which can providemonomeric formaldehyde under the reaction conditions.

Suitable amines are represented by the formula ##STR4## where n, R, a,x, b and c are as defined above with regard to their presence in thefinal product.

Included among the suitable amines are alkylene polyamines where a = 0in the above formula and wherein there are at least threeamino-nitrogens and each non-terminal amino-nitrogen is a tertiaryamino-nitrogen, as in diethylenetriamine, triethylenetetramine,tetraethylenepentamine, hexaethyleneheptamine, dipropylenetriamine,tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine,and hexapropyleneheptamine where each non-terminal amino-nitrogen has analkyl substituent of 1 to 20 carbon atoms, e.g. methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,nonodecyl and eicosyl. The alkyl substituents can be straight chain orbranched chain. Where the alkylene group in the polyalkylenepolyamine isa propylene group, it can be either a 1,2- or a 1,3-propylene group or amixture of 1,2- and 1,3-propylene groups. Mixtures of polyamines can beused.

The preferred polyalkylenepolyamines have n = 3 and x = 1, that is,di-1,3-propylenetriamines of the formula, H₂ N-CH₂ CH₂ CH₂ -N(R)-CH₂ CH₂CH₂ -NH₂, where R is as previously defined. Many of thedipropylenetriamines are commercially available or can be readilyprepared by the well-known reaction comprising condensation of a primaryamine, RNH₂, with acrylonitrile to form, RN(CH₂ CH₂ CN)₂, which uponreduction, for example, by hydrogenation, forms a dipropylenetriamine,RN(CH₂ CH₂ CH₂ NH₂)₂. The primary amine used to prepare thedipropylenetriamine can be any aliphatic primary monoamine of 1 to 20carbon atoms. Preferred are the lower alkylamines of 1 to 4 carbonatoms, most preferably methylamine. Thus, in the preferreddipropylenetriamines R is methyl, ethyl, propyl or butyl, mostpreferably methyl.

Also included among suitable amines are those containing cyclicamino-nitrogen where a = 1 in the above formula, particularly thosecontaining a piperazine ring where n = 2 in the ring structure.Representative examples of such amines are: N-aminoethylpiperazine,N,N'-bis(aminoethyl)piperazine, N-aminoethylpiperazine,N-aminopropylpiperazine and N,N'-bis (aminopropyl)piperazine. All of thesuitable amines discussed above are available commercially or can beprepared readily by methods well-known in the art.

While the compositions of the present invention are more convenientlyprepared by reacting an alkylphenol formaldehyde and a suitable amine bythe above-described Mannich reaction, these compositions can also beprepared by other methods known to those skilled in the art. Forexample, a compound of the formula, Z-NH-CH₂ CH₂ -N(H)-CH₂ CH₂ -NH-Z,where Z is as defined can be prepared by condensing an alkylphenol,formaldehyde and diethylenetriamine. The non-terminal amino-nitrogenwhich is a secondary amino-nitrogen can be alkylated with an alkylhalide to provide the present invention composition. The above secondaryamino-nitrogen can also be converted to a tertiary amino-nitrogen by thereaction of formaldehyde and formic acid whereby the substituent will bea methyl group.

As indicated by the generic formula, the amine composition of thisinvention is characterized by (1) the presence of at least threeamino-nitrogens; (2) the presence of two alkyl- and hydroxy-substituentsbenzyl groups; and (3) each of the non-terminal amino-nitrogen is atertiary amino-nitrogen. Compounds of the invention (where Z and R areas defined) include, among others ##STR5##

Gasolines into which the compositions of the present invention areincorporated are normally mixtures of hydrocarbons boiling in thegasoline range, usually from about 32° to 205° C. They can consist ofstraight chain or branched chain paraffins, cycloparaffins, olefins andaromatic compounds or any mixture of such hydrocarbons obtainable fromstraight run naphtha, polymer gasoline, natural gasoline, thermally orcatalytically cracked hydrocarbon stocks and catalytically reformedstocks. The gasolines can also contain varying amounts of conventionaladditives such as antiknock compounds including tetramethyllead,tetraethyllead, mixed alkylleads, scavenging agents, dyes, antioxidants,antiicing agents, rust inhibitors, detergents, antipreignition agentsare well as intake valve deposit control additives such as nonvolatilemineral lubricating oils of 500 to 1500 SUS viscosity at 38° C, and lowmolecular weight polypropylenes and polybutylenes.

The amount of the present composition to be incorporated into gasolinewill depend upon the particular benefit desired. At about 0.005 weightpercent (12.5 pounds per thousand and barrels ptb), the composition willprovide carburetor detergency. However, at this level some increase inthe intake valve deposit weight may be obtained. At about 0.022 to 0.026weight percent (55 to 65 ptb) there will be obtained both carburetordetergency and a neutral effect on the intake valve deposit weight, i.e.no increase in deposit weight over the base fuel. At about 0.028 weightpercent (70 ptb) and higher, both carburetor detergency and a reductionin the intake valve deposit weight will be obtained. While concentrationgreater than 0.06 weight percent can be used, no additional benefits areseen by such usage.

The following Examples are meant to illustrate the invention.

EXAMPLE 1 ##STR6##

A 75% by weight solution in toluene of polypropylenephenol (preparedfrom polypropylene weight M.W. 840 and phenol), 300 g,methyliminobispropylamine, ##STR7## 14.5 g, and 36% by weight aqueousformaldehyde solution, 17 g, were placed in a reaction flask equippedwith an agitator, a reflux condenser and a Dean-Stark water separator.The reaction mass was refluxed for 11 hours during which time 14.5 ml ofwater was collected and removed. Infra-red analysis of the reactionmixture indicated that the polypropylenephenol had reacted. Theanalytical data on the product (a sample isolated by removing toluene)were: % C, 81.5, % H, 12.0, % N, 2.0 and M.W. 1368. An additional 21.5 gof toluene was added to the reaction mixture to provide the reactionproduct as a 70% by weight solution in toluene.

EXAMPLE 2 ##STR8##

A 75% by weight solution of toluene of polypropylenephenol (preparedfrom polypropylene M.W. 840 and phenol), 300 g, N-aminoethylpiperazine,12.9 g, and a 36% solution of aqueous formaldehyde, 17 g, were placed ina reaction flask equipped with an agitator, a reflux condenser and aDean-Stark water separator. The reaction mixture was refluxed and 15.5ml of water was collected and removed. The reaction mixture was filteredto provide 263 g of clear-brown product.

EXAMPLE 3 ##STR9##

The procedure of Example 2 was followed except thatN,N'-bis(aminopropyl)piperazine, 19.2 g, was used instead ofN-aminoethylpiperazine.

EXAMPLE 4 AND COMPARISONS A AND B Carburetor Detergency

The carburetor detergency test (Onan) is carried out in a singlecylinder engine to which a controlled amount of exhaust gas from anotherengine is mixed with the air supplied to a test carburetor. The testcarburetor throat consists of a two-piece stainless steel liner fittedaround the throttle plate shaft. The liner is easily removed forinspection and rating. The engine is operated under cycling conditionsof one minute idling and three minutes of part throttle for an overalltest period of two hours. A visual rating scale (Onan rating) of 10 fora clean carburetor and 0 for a very dirty carburetor is used. Generally,a rating of about 7 indicates satisfactory carburetor detergency.

Carburetor detergency tests were carried out with the compound ofExample 1. For comparison purposes, the tests were also carried out witha compound of the formula, Z-NH-C₂ H₄ -N(H)-C₂ H₄ -NH-Z, (not of thisinvention, prepared by reacting two moles each of alkylphenol andformaldehyde per mole of diethylenetriamine) and a compound of theformula, Z-NH-C₂ H₄ -N(Z)-C₂ H₄ -NH-Z, (not of this invention, preparedby reacting three moles each of alkylphenol and formaldehyde per mole ofdiethylenetriamine) where Z represents an alkyl- and hydroxy-substitutedbenzyl group where the alkyl group is a polypropylene group of 840molecular weight. It is to be noted that the comparison compounds differessentially from the invention compound used in this test by havingeither a H or Z substituent on the nonterminal amino-nitrogen instead ofa methyl group. The results are summarized in Table 1.

                                      Table 1                                     __________________________________________________________________________    Carburetor Detergency Tests                                                   Example or                       Onan                                         Comparison                                                                             Compound            ptb Rating                                       __________________________________________________________________________    Comparison A                                                                            ##STR10##          15  7.8                                          Comparison B                                                                            ##STR11##          15  5.1                                          Example 4                                                                               ##STR12##          14  7.6                                          __________________________________________________________________________

the compound of Comparative Example A which has a secondaryamino-nitrogen as the nonterminal amino-nitrogen has good carburetordetergency. In Comparative Example B where the compound has a tertiaryamino-nitrogen as the non-terminal amino-nitrogen, carburetor detergencyis lost. Thus, the compound of this invention, which has a tertiaryamino-nitrogen as the nonterminal amino-nitrogen, would also be expectednot to have good detergency. On the contrary, however, the results showthat the compound of this invention at 14 ptb is an effective carburetordetergent (Onan Rating of 7.6).

EXAMPLES 5 TO 7 AND COMPARISONS C AND D Intake Valve Deposit Tests

Intake valve deposits tests were carried out in a 1974 Buick with 455CID engine equipped with an exhaust gas recirculation (EGR) system.Completely reconditioned heads with weighed intake valves were installedbefore the tests. Deposits from piston heads were removed and the intakemanifold was solvent-cleaned. New spark plugs, points, PCV valve, airfilter and oil filter were installed. Carburetor adjustments and timingwere carried out according to the manufacturer's specifications.

Mileage accumulation (6000 miles) was carried out on a ProgrammedChassis Dynamometer According to AMA City Driving Schedule (FederalRegister Vol. 33 No. 2, January 4, 1968). Fuels used were industry-knownIndolene and Indolene containing 2 g/gal. of tetraethyllead antiknockcompound.

At the conclusion of the test, the intake valves were removed andweighed. The deposit weight was expressed as an average weight pervalve. The intake valve tulip deposits were also rated using thestandard CRC merit rating scale wherein a clean valve tulip has a ratingof 10. Deposits on the valve stems were also rated with a clean steamhaving a rating of 10. The stem rating is carried out by comparison witha standard photographic scale. The results are summarized in Table 2.

                  Table 2                                                         ______________________________________                                        Intake Valve Deposit Test                                                     Example           Intake Valve Deposit                                        or Com-                                                                              Additive           (g/    Tulip  Stem                                  parison                                                                              (ptb)     Fuel     valve) Rating Rating                                ______________________________________                                        Compari-                                                                      son C  None      Indolene 2.10   6.2    5.2                                   Example                                                                              of Ex-                                                                 5      ample 1   Indolene 1.99   5.4    8.4                                          (70 ptb)                                                               Compari-         Indolene                                                     son D  None      + 2 g Pb 3.04   6.1    5.3                                   Example                                                                              of Ex-                                                                 6      ample 1   Indolene 4.55   5.6    3.5                                          (14 ptb)  + 2 g Pb                                                     Example                                                                              of Ex-                                                                 7      ample 1   Indolene 2.68   5.7    8.9                                          (70 ptb)  + 2 g Pb                                                     ______________________________________                                    

The above results show that the invention composition at 70 pounds perthousand barrels provides reduction in the intake valve deposit weightsover those of the Comparison (control) fuels. At 14 ptb, there is anincrease of about 50% in the deposit weight. Particularly notable andpromising are the valve stem ratings with the invention composition at70 ptb, Examples 5 and 7. The outstanding improvements in the stemratings also attest to the beneficial effects of the present compositionsince valve stem ratings are often considered to be indicative ofpotential valve sticking.

EXAMPLES 8 to 11 Induction System Deposits

The induction system deposit (ISD) tests were carried out by themodified bench tests of Johnston and Dimitroff, SAE Transactions Vol. 75(1967) Paper No. 660,783. The test consists of spraying gasoline and aironto a heated preweighed metal tube. At the conclusion of the test, themetal tube is removed from the apparatus, washed with heptane andweighed. The weight of the deposit to the nearest 0.1 mg indicates thedeposit-forming tendency of the fuel. The following test conditions wereused:

Fuel: 100 ml Indolene containing 10 volume percent of 10% Indolenedistillation bottoms and 0.05 volume percent of used crankcase oil("Uniflo", 3300 miles)

Fuel Flow: 2 cc/min

Air Flow: 0.05 cu ft/min

Billet Temperature: 288° C.

The effects of the composition of Example 1 on the induction systemdeposits were determined by adding the composition (as 70% solution intoluene) in the indicated amounts to the above-described fuel anddetermining the amount of the deposit formed. The results are expressedin terms of percent deposit weight change compared to the deposit weightobtained with the base fuel. The results are summarized in Table 3.

                  Table 3                                                         ______________________________________                                        Induction System Deposit (ISD) Tests                                          ______________________________________                                                                    ISD                                                                           % Deposit                                                        Additive     Weight                                            Example        (ptb)        Change                                            ______________________________________                                        Example        of Ex-       +49                                               8              ample 1                                                                       14 ptb                                                         Example        of Ex-       +29                                               9              ample 1                                                                       35 ptb                                                         Example        of Ex-       -22                                               10             ample 1                                                                       70 ptb                                                         Example        of Ex-       -39                                               11             ample 1                                                                       105 ptb                                                        ______________________________________                                    

The ISD test results show that the present invention compositionprovides slightly increased induction system deposits at the lowerconcentrations but that the deposit weights are decreased at higherconcentrations. The results show good correlation with the intake valvedeposit tests. By interpolation of the above data, it can be seen thatthe present compositions at 55 to 65 pounds per thousand barrels causeno increase in induction system deposits (and also presumably noincrease in the intake valve deposits) and that at higher concentrationsthey provide for the reduction in the deposit weights.

EXAMPLE 12 AND COMPARISON E Octane Requirement Increase

The effect of the invention compositions on the octane requirementincrease (ORI) of an engine was determined on a clean Ford 302 CID V8engine on a test stand. The fuel was unleaded Indolene. The engine wasoperated on a modified AMA driving schedule (Federal Register Vol. 33No. 2, Jan. 4, 1968) which simulated an urban and suburban driving cycleaveraging about 30 miles per hour. The octane requirements weredetermined using primary reference fuels, the test being continued untilequilibrium octane requirement of the engine was established.

The composition of Example 1 was added to the fuel as a 70% by weightsolution in toluene at 100 pounds per thousand barrels (ptb) therebyproviding the composition at 70 ptb. Additionally, at the end of thetest, the intake valves were inspected for deposits and cleanliness. Theresults, summarized in Table 4, show that the composition of theinvention does not add to the octane requirement increase of the fueland reduces the intake valve deposit weight and keeps the valves cleanat the concentration employed.

                  Table 4                                                         ______________________________________                                        Octane Requirement Increase (ORI)                                             ______________________________________                                        Ex-                                                                           ample                  Intake Valves                                          ______________________________________                                        or     Addi-    to      Total      Wt.  Tulip Stem                            Compa- tive     Stable  Opera-     g/   Rat-  Rat-                            rison  (ptb)    ORI     tion  ORI  valve                                                                              ing   ing                             ______________________________________                                        Compa-                                                                        rison                                                                         E      None     500     633   9.4  3.3  5.3   3.8                             Ex-    of Ex-                                                                 ample  ample                                                                  12     1        375     592   8.0  0.3  7.7   7.5                                    (70 ptb)                                                               ______________________________________                                    

1. A composition of the formula

    ZNHC.sub.n H.sub.2n (N(R)C.sub.n H.sub.2n) .sub.b (NH).sub.c Z

wherein Z is an alkyl- and hydroxy-substituted benzyl group wherein thealkyl has 20 to 1000 carbon atoms; n is 2 or 3; R is an alkyl of 1 to 20carbon atoms; b is 1 to 5 and c is
 1. 2. A composition according toclaim 1 wherein the alkyl group in Z has 50 to 200 carbon atoms.
 3. Acomposition according to claim 2 wherein n = 2, b = 1 to 5, and c = 1.4. A composition according to claim 2 wherein n = 3, b = 1 to 5, and c=
 1. 5. A composition according to claim 2 wherein the alkyl group in Zhas 50 to 75 carbon atoms.
 6. A composition according to claim 5:Znhc₃h₆ n(r)c₃ h₆ nhzwherein R is an alkyl group of 1 to 4 carbon atoms.
 7. Acomposition according to claim 6:Znhc₃ h₆ n(ch₃)c₃ h₆ nhz.
 8. acomposition comprising a major proportion of a normally liquidhydrocarbon boiling in the gasoline range and from 0.005 to 0.06 weightpercent of the composition according to claim
 1. 9. A compositioncomprising a major proportion of a normally liquid hydrocarbon boilingin the gasoline range and from 0.005 to 0.06 weight percent of thecomposition according to claim
 7. 10. A concentrated solution in ahydrocarbon solvent boiling in the gasoline boiling range of 32° C to205° C, of from 10 to 90 weight percent of the composition according toclaim 1.